# Re: 10D Circle of Confusion

Discussion in 'Digital Photography' started by jgerard, Jul 17, 2003.

1. ### jgerardGuest

Hello,

I have the near/far distance charts for my Canon EOS 10s film camera. Does
anyone know the Circle of Confusion number for the 10D. Is it the same as
my 10s?

Thanks,

John

jgerard, Jul 17, 2003

2. ### Bart van der WolfGuest

"Katie Piecrust" <NoSpam!> wrote in message
news:...
> I just made a hyperfocal chart using MS Excel for my 10D. A CoC of around
> 0.019 (based on an 8x12 enlargement viewed from 10 or 15 inches) for the
> D30/D60/10D is a generally good value I believe (based on what I've been
> reading around the net at least). If you have a CoC your happy with when
> using 35mm film, just divide it by 1.6 to get an approximate number for

your
> 10D. That's the easiest way. Hopefully my info is correct since I'm just
> learning about CoC at the moment myself.

0.019 sounds reasonable for full/uncropped frames viewed from a distance
equal to the image diagonal.. I usually follow a rule of thumb (which is
exactly that, nothing more than a rule of thumb) of the effective sensor
area's diagonal in mm, divided by the square root of 2, divided by 1000,
which equates to ...
0.01926 ! For 35mm film that would have equated to 0.03059, and 0.03 is a
commonly used number for 35mm film.

Again, what's good for one person, isn't necessarily good for another, but
one has to start somewhere, so 0.019 mm it is and that is almost a factor
1.6 smaller.

Bart

Bart van der Wolf, Jul 17, 2003

3. ### john woodGuest

in article 8wCRa.59827\$,
jgerard at wrote on 17/7/03 8:09 PM:

> Hello,

Does anyone know the Circle of Confusion number for the 10D. Is it the
same as my 10s?

Some 55+ years ago when I was being taught photography, we finally agreed
that the circle of confusion was a group of people gathered around a plate
camera discussing focus!

john wood, Jul 18, 2003
4. ### Dave MartindaleGuest

"Bart van der Wolf" <> writes:

>Again, what's good for one person, isn't necessarily good for another, but
>one has to start somewhere, so 0.019 mm it is and that is almost a factor
>1.6 smaller.

If you know what circle of confusion you like to use in 35 mm, just
divide by the 1.6 "focal length conversion factor". This factor is the
ratio of the size of a 35 frame to the sensor size, so it's the
additional amount that you need to enlarge the digital image to get the
same size print as a 35 film frame. So if you use 30 microns for your
35 mm CoC, and 30/1.6 for your 10D CoC, both circles of confusion end up
the same size on the print, whatever size of print you choose.

Dave

Dave Martindale, Jul 18, 2003
5. ### Randall AinsworthGuest

> Some 55+ years ago when I was being taught photography, we finally agreed
> that the circle of confusion was a group of people gathered around a plate
> camera discussing focus!

Randall Ainsworth, Jul 18, 2003
6. ### Katie PiecrustGuest

I do, because knowing the various hyperfocal distances to focus at for a
certain focal length & aperture combination can be very helpful, particular
for doing wide angle evening/night scenics when you can't auto-focus. Plus
they are different for the D30/D60/10D than 35mm film, so it helps to know
the math (or in my case, make an automated Excel cheat sheet). So now when I
"go out and take pictures", I can take even better pictures.

PS: The ones I did the other night turned out blurry because I didn't have
charts made yet, and one would have been a beautiful keeper (aurora, sunset,
stars, and a strong foreground that nature set up just for me... was very
nice... sniffle).

"Randall Ainsworth" <> wrote in message
news:180720030535157550%...

> Some 55+ years ago when I was being taught photography, we finally agreed
> that the circle of confusion was a group of people gathered around a plate
> camera discussing focus!

Katie Piecrust, Jul 18, 2003
7. ### Bart van der WolfGuest

"Dave Martindale" <> wrote in message
news:bf84sf\$pbg\$...
SNIP
> If you know what circle of confusion you like to use in 35 mm, just
> divide by the 1.6 "focal length conversion factor".

That's right. However, not everybody has a reference in 35mm, so they might
want to calculate it somehow as a starting point.

Bart

Bart van der Wolf, Jul 18, 2003
8. ### jgerardGuest

Hello,

I was given this CoC number (or what ever you call it), some years ago for
my 10s film camera so it sounds like I can take that number as the starting
point.
Also, I have a couple of speadsheets at different focal lengths and these
really help to know what is in focus. Expecially right know since I am
still trying to understand how the 10D one, focuses and two, how it is
selecting the apperature setting for different shooting situations. It
isn't working as easily for me just to go out and shoot. Half of my shots
come out slightly on the blured side.

John

"Bart van der Wolf" <> wrote in message
news:3f18251e\$1\$49100\$4all.nl...
>
> "Dave Martindale" <> wrote in message
> news:bf84sf\$pbg\$...
> SNIP
> > If you know what circle of confusion you like to use in 35 mm, just
> > divide by the 1.6 "focal length conversion factor".

>
> That's right. However, not everybody has a reference in 35mm, so they

might
> want to calculate it somehow as a starting point.
>
> Bart
>
>

jgerard, Jul 18, 2003
9. ### GAOGuest

Go here for an online dof calculator/CoC for 10d and other camera models.

http://dfleming.ameranet.com/dofjs.html

Gene

"Bart van der Wolf" <> wrote in message
news:3f18251e\$1\$49100\$4all.nl...
>
> "Dave Martindale" <> wrote in message
> news:bf84sf\$pbg\$...
> SNIP
> > If you know what circle of confusion you like to use in 35 mm, just
> > divide by the 1.6 "focal length conversion factor".

>
> That's right. However, not everybody has a reference in 35mm, so they

might
> want to calculate it somehow as a starting point.
>
> Bart
>
>

GAO, Jul 19, 2003
10. ### Bart van der WolfGuest

"jgerard" <> wrote in message
news:AhZRa.61537\$...
SNIP
> It isn't working as easily for me just to go out and shoot. Half of my

shots
> come out slightly on the blured side.

The Auto Focus sensors benefit from having enough light (so large aperture
lenses focus easier and bright light helps), and they usually focus faster
on vertically oriented contrast features. Try finding those, even if outside
the frame you're composing, lock or maintain that focus distance and
recompose and take the image.

Bart

Bart van der Wolf, Jul 19, 2003